The present invention will be described relative to a balance or scale, even though it is suitable for any measuring instrument having a multi-segment display. In general, a seven segment indicator having three at least approximately horizontal and four at least approximately vertical segments will be concerned. However, displays with a greater or lesser number of segments, as well as displays utilizing points rather than segments to construct the symbols, are to be included.
A balance of the type described herein is disclosed in U.S. Pat. No. 4,200,896 (corresponding to Swiss Pat. No. 618,508). In this balance, the numerical display may be replaced by a qualitative display when desired. This may be the case when the actual measured value is not of interest, but only whether the measured weight exceeds or is less than a reference weight. Under these conditions, in the known scale, the position of a line of horizontal segments indicates the result of the comparison: Segments of the upper row are illuminated when the weight exceeds the reference value, while those in a lower row are illuminated when the measured value is less than the reference value. A middle row of horizontal segments is used to indicate that the measured value is within a certain region, that is greater than a lower limit value and less than an upper limit value.
This type of display has the following disadvantage: Unless the operator looks at the display from a close distance, it is difficult to tell exactly whether the illuminated horizontal segments are in the middle or upper (or possibly lower) row. It is easy for an operator to make a mistake and thereby arrive at incorrect conclusions.